I suppose a performance hit is to be expected given that the new textures are in 2048x2048...personally, I didn't tried the pack but I am not sure that the new textures are really an improvement (it was certainly a lot of work for the modder though ). From the screenies published here (in French but you don't need to understand to see the screenshots) tiling seems more visible to me and I can't say that I am very fond of all those rocks...to each its own I guess...to me pure "photo-realistic" textures != automatical improvement .